Portable scaffold



April 15, 1969 E. J. MAGEE 3,438,459

PORTABLE S CAFFOLD Filed Nov. 30 1966 Sheet of 2 EUGENE J. M4655 zdwz MM2104/ az w ww Affvrn e 98 Filed Nov. 30, 1966 [)VVHVTOR. Euesms J. M4655zwdumaw uw United States Patent US. Cl. 182-119 6 Claims ABSTRACT OF THEDISCLOSURE A scaffold which is characterized by two extension laddershaving work planks disposed therebetween. The work planks are associatedwith the upper part of the extension ladders and raised and loweredelectrically. Special fittings leads to extreme versatility insofar aslength, width and height of the scaffold.

Background of the invention This invention relates to scaffolds and moreparticularly relates to a scaffold which is readily adjustable andfurther which is readily assembled and dismantled.

While a number of scaffolds depending on ladders have been disclosed inthe prior art, there has long been a need for a scaffold which isreadily adjustable for width, height and length, and which further maybe assembled and dismantled with relative ease. The present inventionprovides such a scaffold by providing means for automatical- 1y raisingand lowering the scaffold and by further providing quick-hitch fittingsand length guide means.

Summary of the invention One embodiment of a scaffold in accord with thepresent invention includes two extension ladders set edgeways. Thebottom ladders are set in carriages which include locking casters withlegs adjustable to adapt to the terrain and which are clamped to theladders by hook bolts which reach through the carriage and around therails of the ladder.

The ladders are held in a vertical position with runners and bracesadapted for quick adjustment, assembly or dismantling. The ladders aresecured to a building; surface with bumpers and props. The bumpersfurther serve to splice two sections of the scaffold together if a widerscaffold is desired.

The horizontal work planks can be used either resting on the rungs whenthe raising or lowering of the scaffold is not important, or resting onshelves which are attached to the upper part of the extension laddersand raised or lowered electrically or by a hand crank.

The extension ladders may be of wood, metal or any other suitablematerial and may be of any height, from six to sixty feet being thenormal range. The work planks may be either of wood or metal or anyother suitable material, and of any length desired, although six feet isnormally as short as is desirable.

Therefore, it is an object of the present invention to provide animproved scaffold characterized by its versatility.

Brief description of drawings The full nature of the invention will beunderstood from the accompanying drawings and the following descriptionand claims.

FIG. 1 is a side view of a scaffold in accord with the presentinvention.

FIGQ'Z is an end view of the scaffold of FIG. 1.

FIG. 3 is a perspective view of a bracket adapted to be secured to aladder rail and having a mounting flange adapted to receive aquick-hitch fitting.

FIG. 4 is an exploded view of a quick-hitch assembly fitting from thebraces and ladder rails.

FIG. 5 is a section View of the assembled quick-hitch fitting of FIG. 4.

FIG. 6 is a perspective view of a quick-hitch washer for the abovefitting.

FIG. 7 is a perspective view of the bracket fittings for the runners.

Description of the preferred embodiment Referring more particularly tothe drawings, one embodiment of the scaffold in accord with the presentinvention is shown generally at 10. The scaffold includes two extensionladders shown generally at 11 which have a bottom ladder 12 and a topladder 13. The ladders are held in position by an arrangement ofhorizontal runners 14 and diagonal braces 15. The runners and braces arereceived in quick-hitch fittings shown generally at 16 and 17,respectively.

Fittings 17 are permanently bolted to the ends of each brace (indicatedby dotted lines). Each fitting is a substantially H-shaped member. Theend of the brace abuts the inner surface of the end wall 18 of thefitting. The brace is secured within the fitting via bolts (not shown)which are received through apertures 19 in the fitting side walls 20 and21. The upstanding arm 21A extends outwardly beyond end wall 18 to forma mounting tongue. The mounting tongue shown in the illustrativeembodiment is tapered at its distal end so as to conform to theconfiguration of the ends of the bracket members shown generally at 22.

The fitting shown generally at 16 serves to mount the braces and runnersto the ladder rails (dotted line). Side wall 23 engages a side wall of abumper or runner. Wall 24 engages the inner side surface of the ladderrail and mounting flange 25 is adapted to be removably coupled tofittings 17 and 46.

The quick-change fittings consist of a T-head bolt 30, a shoulder washer31, a tension washer 32, a lock nut 33 and a wing nut 34. This can beadjusted so the exact tension can be held on a T-head bolt to hold it inthe slot 36 in the mounting flange 25.

A quick-hitch washer 37 has a central aperture 38 which is aligned withslot 36 of the mounting flange. The quick-hitch washer has a pluralityof spaced fingers 39 which extend outwardly from and are perpendicularto the face of the washer. The width and spacing of the fingerscorrespond to the width of the substantially rectangular apertures 40located on either side of slot 36. The outer edge 39A of the fingers areconcave and of such a length that they protrude through the mountingflange 25. When the bolt is in place as shown in FIG. 5, the head 30A isseated on the concave surface of the fingers. When the assembly ispushed in, the T-head is moved out of engagement with the concavesurfaces of the fingers. By turning the bolt and aligning the T-head ofthe bolt with the slot 36, the entire assembly can be removed. Byreversing the procedure, the entire assembly can be easily assembled.Therefore, a quickhitch fitting which is extremely convenient and easyto manipulate has been provided. It will be noted that the mountingflange has two slots 36, one adjacent the top of the flange and oneadjacent the bottom of the flange. Thus, flexibility in the positioningof the brace is provided. It is obvious that a series of intermediateslots could be provided for even greater flexibility.

The braces are afiixed to the runners via brackets 22. The bracketsshown generally at 22 have a flat bracket member 45 which fits flushagainst the runner and a bracket member 46 which is substantiallyC-shaped to fit over the side of the runner and which has mountingflanges 46A which interfit with the member 45. Two

bracket members 46 may be used facing each other instead of thecombination of bracket members and 46 when it is necessary to splice tworunners together to obtain a longer scaffold. Brackets 22 and fittings17 are joined by means of a conventional bolt, nut and washer.

It will be noted that each of the runners have a plurality of spacedholes 51 therein. The holes are drilled in pairs at predeterminedintervals. Bracket member 46 has an aperture 46B which is adapted to bealigned with apertures 51. Thus, by loosening bracket 22 and sliding thebracket to the appropriate position, the length of the scaffold isreadily adjusted. This arrangement greatly simplifies the task ofsquaring off the scaffold. The workmen only have to remember to use thepair of holes selected, the ones nearest the end of the runner for thebottom part of the ladder and the holes of the pairs nearest the centerfor the upper part of the ladder. With this pair arrangement the runnersare interchangeable between the upper and lower ladders by changingbracket member 46 to the proper holes.

In order to brace the scaffold, a bumper is mounted to the top part ofthe lower extension ladder. The bumper is placed perpendicular withrespect to the vertical work surface so that the scaffold will be heldsolidly between the prop 61 and the building to be worked on. Similarbumpers can be used as high as sixty feet or more, so that the top partsof the ladders can be tied securely against buildings, and be releasedwhen the work is completed. The bumpers serve to hold the scaffoldsolidly to the building and still provide working space. If the scaffoldshould be used in a large interior space, the bumper which is normallytwo by four could be extended as long as twenty-four feet and twosections of the scaffold locked together. In this instance, the prop 61would not be needed. The props are connected with universal swiveljoints 62 which allow the props to be folded back flush with the rest ofthe scaffolding when the scaffolding is moved through gates and othernarrow areas. The work planks rest on shelves 71. The work planks areseated on the shelves which hook over the ladder rungs so that they canbe mounted at various places on the ladder.

The runners above each work plank on the upper ladder are used asprotective back rails as well as functioning in connection with thebraces to strengthen and stabilize the upper part of the ladder. Each ofthe bottom ladders has a plate which is mounted to the lower end of eachof the bottom ladders. Each plate has two slots 81 which allow fordifferences in widths of various ladders. Each of the plates have aninturned bottom flange 82 on which the ends of the ladder rails seatagainst.

Conventional two-way locking casters 83 are mounted in the plate. Theheight of the casters is adjusted by telescoping square or tubularmembers 34. The ends of plate 81 have apertures 85 drilled therein. Theheight adjusting members 84 also have spaced apertures 86 drilledtherein. By adjusting the position of the telescoping member 84 withrespect to the plate, the height of the scaffold may be adjusted. Thisis particularly important where the ter: rain is uneven, or where thescaffold is to be set up on steps. It is a simple matter to square offthe scaffold by adjusting the position of the members 84 with the plate.Once again, the workmen only have to match up the corresponding holes oneach member to square off the scaffold. Thus, the scaffold is readilymoved from one position to another and is readily adjusted fordifferences in the terrain or floor area.

The height of the scaffold is electrically adjusted by a motor and wincharrangement shown generally at 90 and indicated by dotted lines inFIG. 1. The cable (not shown) runs underneath the work plank. The cable92 is placed around a pulley 93 as shown in FIG. 2 and strung betweenthe rungs of two ladders up to a pulley 94 suspended between the two toprungs of the bottom ladder. The cable goes down and is attached to thebottom rung 95 of the top ladder. The motor operates two drums. Thus, inorder to adjust the height of the scaffold, the upper ladder is movedelectrically with respect to the lower ladder. Any number of pulleyarrangements may be utilized.

One arrangement includes a drive pulley mounted on one of the shelves asindicated in the drawing. A trolley pulley is associated with the drivepulley. A first cable travels under the trolley pulley and upwardlybetween the rungs of the lower ladder and the rungs of the upper ladder,over a return pulley which is mounted adjacent the rungs of the ladderand under the work plank and finally anchored at the opposite end of thework plank. A second cable is run over the trolley pulley and from thereto the opposite end of the scaffold. There is a first trolley pulley anda second trolley pulley mounted to the shelf means at the opposite endof the scaffold. The second cable travels over the first trolley pulley,under the second trolley pulley, upwardly through the openings betweenthe rungs of the upper ladder and the rungs of the lower ladder andaround the return pulley, which is mounted near the rungs of the ladderas indicated by numeral 94. The cable then returns downwardly throughthe openings between the rungs of the upper and lower ladder and isanchored under the work plank.

It is obvious that the ladders may be also adjusted by hand, that is,the pulley system may be operated manually. However, with the electricarrangement, the workmen on a work plank need only activate the electricmotor until the proper height has been attained and then deactivate themotor. The entire structure provides for numerous combinations of sizesand heights of the scaffold.

While the invention has been disclosed and described in some detail inthe drawings and foregoing description, they are to be considered asillustrative and not restrictive in character, as other modificationsmay readily suggest themselves to persons skilled in this art and withinthe broad scope of the invention, reference being had to the appendedclaims.

The invention claimed is:

1. In a scaffold, the combination comprising:

first and second scaffold members; a first bracket on said firstscaffold member and having a portion with slot therein for receiving ahead of a T-shaped bolt, and having first and second apertures onopposite sides of said slot; a fitting mounted to said second scaffoldmember and having a portion with an aperture therein disposed inregistry with said slot; a washer having an aperture for receiving theneck portion of said T-shaped bolt therethrough, and having a pair offingers disposed on opposite sides of said aperture and spaced tocorrespond to said apertures of said bracket and received therein, saidfingers being generally perpendicular to a face of said washer and saidfingers having cavitied end surfaces for seating said bolt head therein;a nut threadedly received on the neck of said bolt, with said aperturedportion of said fitting and the slotted portion of said bracket beingdisposed between said bolt head and said nut; resilient loading meansdisposed on the neck of said bolt between said nut and said fittingportion and urging the bolt head into said cavitied ends of said fingersto hold said fitting and bracket portions together; said loading meansbeing adapted to accommodate intentional release of said bolt head fromsaid cavitied finger ends for turning and removal of said bolt headthrough said slot for quick separation of said bracket portion from saidfitting portion.

2. In a scaffold, the combination comprising:

(a) a pair of extension ladders, each of said extension ladders having atop ladder and a bottom ladder;

(b) a first runner bridging said top ladders of said extension ladders,a second runner bridging said bottom ladders, each of said runnershaving a first end and a second end;

(c) coupling means cooperatively associated with each of said first andsecond ends of said first and second runners for coupling each of saidends to said ladders;

(d) receiver means cooperatively associated with said ladders forreceiving said coupling means associated with said runners;

(e) means for bracing said runners, said bracing means having a firstend cooperatively associated with a ladder and a second endcooperatively associated with a runner;

(f) means for coupling said first end of said bracing means with saidrunners, said runners having complementary coupling means;

(g) fitting means for coupling said second end of said bracing meanswith said ladders, said ladders having complementary coupling means;

(h) a first work plank bridging said top ladders;

(i) means for coupling said work plank to said ladders;

(j) means for adjusting the height of said first work plankcooperatively associated with said extension ladders; and

(k) means for maintaining said scaffold in a fixed position in relationto a work area, said means being cooperatively associated with saidextension ladder;

said complementary coupling means of paragraph (g) for coupling saidsecond end of said bracing means with said ladders comprising a bracketmeans aflixed to an inside wall of a ladder rail, said bracket meanshaving a mounting flange extending outwardly therefrom, said mountingflange having a slot for receiving a head of a T-shaped bolt, a firstsubstantially rectangular aperture on one side of said slot and a secondsubstantially rectangular aperture on the other side of said slot; aquick-hitch washer disposed between said mounting flange of said bracketmeans and a mounting tongue of said fitting means; said quickhitchwasher having a centrally located aperture for receiving the neckportion of said T-shaped bolt therethrough, said mounting tongue havinga corresponding aperture, said quick-hitch washer additionally having aplurality of fingers disposed about said centrally located aperture andspaced to correspond to said first and second substantially rectangulartapertures of said mounting flange, said fingers being perpendicular tothe surface of said quick-hitch washer; said fingers having concave endsurfaces for seating said bolt head thereon; a wing nut threadedlyreceived on said neck of said T-shaped bolt, tension adjusting meansdisposed about said bolt neck between said mounting tongue and said wingnut, washer means disposed about said bolt between tension adjustingmeans and said wing nut, and a locking nut disposed about said bolt atits outer end, said locking nut abutting said wing nut, said couplingmeans adapted to be removable when pressure is exerted on said wing nutso as to compress said tension adjusting means whereupon said bolt headis movable out of engagement with said concave surfaces of said fingers,and whereupon by rotating said wing bolt about said head is aligned withsaid slot and said bolt is removable from said mounting flange.

3. In a scaffold in accord with claim 1, said first work plank beingdisposed below said first runner, said first runner additionally servingas a safety rail for a workman; said means for coupling said work plankto said ladders being shelf means adapted to removably engage a ladderrung and be supported thereby, said work plank having a shelf meansassociated at each end thereof.

4. In a scaffold in accord with claim 3, said height adjusting meansbeing an electric motor means operable to raise and lower said topladder, thereby raising and lowering said first work plank.

5. In a scaffold in accord with claim 4, the combination additionallycomprising a second work plank bridging a bottom part of said topladders, shelf means removably engaged over the rungs of said topladders, the ends of said work plank seated on said shelves.

6. In a scaffold in accord with claim 5, said scaffold additionallycomprising caster means afiixed to the lower end of each of said bottomladders, said caster means being adjustable so as to compensate foruneven terrain.

References Cited UNITED STATES PATENTS 1,692,664 11/1928 Kirsc-h 182-2082,933,150 4/1960 Balogh 182-208 2,951,549 9/1960 Holan et al 182-208506,561 10/1893 Smith 182-119 711,384 10/1902. Carman 182-119 734,3217/1903 Hagan 182-118 771,878 10/1904 Laughlin 182-118 1,351,053 8/1920Macklem 182-119 1,549,270 8/1925 Laber 182-118 3,071,206 1/1963 Kristen182-119 REINALDO P. MACHADO, Primary Examiner.

US. Cl. X.R. 182-179 U.S. DEPARTMENT OF COMMERCE PATENT OFFICEWashington, 0.0. 20231 UNITED STATES PATENT OFFICE CERTIFICATE OFCORRECTION Patent No. 3,438,459 April 15 196' Eugene J. Magee It iscertified that error appears in the above identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Column 6, line 12, the claim reference numeral "1" should read 2 signedand sealed this 14th day of April 1970.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer

